This is an application for renewal of a longstanding program to provide intensive training in modern methods of nephrologic research to clinically trained individuals with the M.D. or M.D./Ph.D. degree. Continued funding of seven stipends per year is requested for this joint training program that provides support for both "adult" and pediatric nephrology fellows. Although the highest priority of this program is to train physician-scientists, basic scientist trainees with the Ph.D. degree who are strongly committed to careers in kidney research are also supported whenever possible. Each year 3-4 new trainees are recruited into the program after completing residency training in internal medicine or pediatrics. Only fellows with a strong commitment to multi-year research training are recruited into the program. Training is provided in both laboratory-based and patient-oriented research. The training faculty is drawn from multiple clinical and basic science departments (Internal Medicine, Pediatrics, Cellular and Molecular Physiology, Cell Biology, Epidemiology and Public Health, Genetics, Immunobiology, Pathology, Pharmacology) and spans diverse biomedical disciplines relevant to kidney disease research (electrolyte physiology and pathophysiology, cell biology and experimental pathology, developmental biology and genetics, immunology and transplantation, vascular biology, clinical epidemiology and biostatistics). Although the core of research training is provided through work on a selected research topic under the supervision of an individual preceptor, training is enhanced by a broad array of teaching conferences, seminars and courses. Indeed, fellows may enroll in degree programs specifically designed for training clinician investigators including the Investigative Medicine Ph.D. program, and the Program in Chronic Disease Epidemiology that leads to a Master of Science in Epidemiology and Public Health. This program has trained many current leaders in academic nephrology, and the recent track record continues to be outstanding with a high number of trainees successfully transitioning to mentored career development faculty awards from the NIH (e.g. K08) or private agencies (e.g. American Heart Association).